“Microbes explain the world,” says Erin McKenney ’11 MS, associate professor in the College of Agriculture and Life Sciences. For McKenney, who studies digestive microbiomes, those collections of bacteria and microorganisms aid in understanding how animals interact with their environments.

That perspective led McKenney and collaborators to ask a deceptively simple question: What can the gut of a North Carolina black bear reveal about the world around it?

Quite a lot, it turns out.

For many animals, digestion is a team effort. Gut microbiomes unlock nutrients animals can’t otherwise access. Cows, for example, rely on armies of microbes to break down tough plant material. Humans, too, depend on trillions of microbial partners to digest food. 

Bears are different. McKenney describes their digestive tract as a “garden-hose gut” — a term they coined for a simple digestive system that moves food through in as little as three hours. This leaves less time for bears’ microbiomes — and immune systems — to process all the microbes that arrive with their food.

That simplicity, combined with a wide-ranging diet, makes bears a moving ecological archive. 

“ . . . their gut microbiomes reflect a constantly changing menu shaped by the surrounding landscape.”

“Bears are consummate omnivores,” says McKenney. “They vacuum up whatever they encounter across the landscape that’s edible. Because of that, their gut microbiomes reflect a constantly changing menu shaped by the surrounding landscape.”

By studying those microbial communities, McKenney and their team established a baseline understanding of healthy wild bears. Future studies can compare bear microbiomes over time, asking whether habitat loss, changing diets or other environmental pressures leave clues in the gut.

McKenney’s work raises questions about bears’ roles in ecosystems, suggesting they may transport microbial communities and potentially even antibiotic-resistant pathogens.

Wildlife microbiome research is exciting to McKenney because much of what scientists know about gut microbiomes comes from studying humans, livestock and laboratory animals. Wildlife, McKenney says, offers a chance to see how these systems function in the natural world and how our choices are reshaping the environments we share.  

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